From 1ad08d99984d1801a3b7605ebdec83b171aed7bb Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop+git@gmail.com>
Date: Sat, 7 Mar 2009 19:17:47 +0000
Subject: [PATCH] cleaning up shapes/Cyl a bit

git-svn-id: svn://anubis/fart/trunk@190 7f9b0f55-74a9-4bce-be96-3c2cd072584d
---
 shapes/Cyl.cc | 28 ++++++++++++++++++----------
 shapes/Cyl.h  |  1 +
 2 files changed, 19 insertions(+), 10 deletions(-)

diff --git a/shapes/Cyl.cc b/shapes/Cyl.cc
index daab4b8..79cb68c 100644
--- a/shapes/Cyl.cc
+++ b/shapes/Cyl.cc
@@ -17,6 +17,8 @@ Cyl::Cyl(double bottom_radius, double top_radius, double height)
     if (m_height == 0.0)
         m_height = 1.0;
     m_slope = (m_top_radius - m_bottom_radius) / m_height; /* rise over run */
+    if ( ! FP_EQUAL(m_slope, 0.0) )
+        m_inv_slope = -1.0 / m_slope;
 }
 
 Shape::IntersectionList Cyl::intersect(refptr<Shape> _this, const Ray & ray)
@@ -34,7 +36,7 @@ Shape::IntersectionList Cyl::intersect(refptr<Shape> _this, const Ray & ray)
         {
             Vector isect_point = ray_inv[solutions.results[0]];
             if (isect_point[0]*isect_point[0] + isect_point[1]*isect_point[1]
-                    < m_bottom_radius_2)
+                    <= m_bottom_radius_2)
             {
                 res.add(Intersection(_this,
                                      m_transform.transform_point(isect_point)));
@@ -52,7 +54,7 @@ Shape::IntersectionList Cyl::intersect(refptr<Shape> _this, const Ray & ray)
         {
             Vector isect_point = ray_inv[solutions.results[0]];
             if (isect_point[0]*isect_point[0] + isect_point[1]*isect_point[1]
-                    < m_top_radius_2)
+                    <= m_top_radius_2)
             {
                 res.add(Intersection(_this,
                                      m_transform.transform_point(isect_point)));
@@ -97,7 +99,7 @@ Shape::IntersectionList Cyl::intersect(refptr<Shape> _this, const Ray & ray)
         if (solutions.results[i] >= 0.0)
         {
             Vector isect_point = ray_inv[solutions.results[i]];
-            if (isect_point[2] >= 0.0 && isect_point[2] <= m_height)
+            if (isect_point[2] > 0.0 && isect_point[2] < m_height)
             {
                 res.add(Intersection(_this,
                                      m_transform.transform_point(isect_point)));
@@ -124,19 +126,25 @@ Vector Cyl::getNormalAt(const Vector & pt)
     }
     else
     {
-        if (m_slope == 0.0)
+        if ( FP_EQUAL(m_slope, 0.0) )
         {
             normal = Vector(local_pt[0], local_pt[1], 0.0);
-            normal.normalize();
         }
         else
         {
-            double norm_slope = -1.0 / m_slope;
-            double z = sqrt(local_pt[0]*local_pt[0] + local_pt[1]*local_pt[1])
-                           * norm_slope;
-            normal = Vector(local_pt[0], local_pt[1], z);
-            normal.normalize();
+            double x = local_pt[0];
+            double y = local_pt[1];
+            double dist = sqrt(  local_pt[0] * local_pt[0]
+                               + local_pt[1] * local_pt[1] );
+            if (dist > 0.0)
+            {
+                double scale = 1.0 / dist;
+                x *= scale;
+                y *= scale;
+            }
+            normal = Vector(x, y, m_inv_slope);
         }
+        normal.normalize();
     }
 
     return m_transform.transform_normal(normal);
diff --git a/shapes/Cyl.h b/shapes/Cyl.h
index eeef786..e1eddf0 100644
--- a/shapes/Cyl.h
+++ b/shapes/Cyl.h
@@ -18,6 +18,7 @@ class Cyl : public Shape
         double m_top_radius_2;
         double m_height;
         double m_slope;
+        double m_inv_slope;
 };
 
 #endif